Vehicle drive control apparatus and method

A vehicle drive control apparatus, comprising:

• an engine that generates power through combustion of fuel;
• an automatic transmission that transmits a reverse input from a driving wheel to the engine and automatically performs a gear shifting among a plurality of forward gear stages each having a different gear ratio;
• and
• a controller that:
• executes a fuel cut control for stopping supply of the fuel to the engine upon establishment of a fuel cut condition including that a vehicle is in a coasting state where a throttle valve of the engine is fully closed, and an engine speed is equal to or higher than a predetermined fuel cut release engine speed;
• and
• changes a coast down vehicle speed and upshifting vehicle speed in accordance with a change in the fuel cut release engine speed so as to continue the fuel cut control irrespective of the change in the fuel cut release engine speed.

A vehicle drive control apparatus, comprising:

• an engine that generates power through combustion of fuel;
• an automatic transmission that transmits a reverse input from a driving wheel to the engine and automatically performs a gear shifting among a plurality of forward gear stages each having a different gear ratio;
• and
• a controller that:
• executes a fuel cut control for stopping supply of the fuel to the engine upon establishment of a fuel cut condition including that a vehicle is in a coasting state where a throttle valve of the engine is fully closed, and an engine speed is equal to or higher than a predetermined value;
• executes a control of the automatic transmission for downshifting at a predetermined coast down vehicle speed so as to continue the fuel cut control in the coasting state;
• and
• executes a control of changing a downshifting speed such that the downshifting speed increases as an increase in a deceleration of the vehicle.

A vehicle drive control apparatus, comprising:

• an engine that generates power through combustion of fuel;
• an automatic transmission that transmits a reverse input from a driving wheel to the engine and automatically performs a gear shifting among a plurality of forward gear stages each having a different gear ratio;
• a fluid power transmission device interposed between the automatic transmission and the engine for transmitting power through fluid, the fluid power transmission device having a lock-up clutch;
• and
• a controller that:
• executes a fuel cut control for stopping supply of the fuel to the engine upon establishment of a fuel cut condition including that a vehicle is in a coasting state where a throttle valve of the engine is fully closed, and an engine speed is equal to or higher than a predetermined value;
• executes a control for engaging the lock-up clutch upon establishment of a lock-up clutch engagement condition including that the vehicle is in the coasting state;
• executes a control of the automatic transmission for downshifting at a predetermined coast down vehicle speed so as to continue the fuel cut control in the coasting state;
• and
• executes a feedback control of an engagement torque of the lock-up clutch such that a slip amount of the lock-up clutch reaches a target slip amount upon execution of the control of the automatic transmission for downshifting.

A vehicle drive control apparatus, comprising:

• an engine that generates power through combustion of fuel;
• an automatic transmission that transmits a reverse input from a driving wheel to the engine and automatically performs a gear shifting among a plurality of forward gear stages each having a different gear ratio;
• a fluid power transmission device interposed between the automatic transmission and the engine for transmitting power through fluid, the fluid power transmission device having a lock-up clutch;
• and
• a controller that:
• executes a fuel cut control for stopping supply of the fuel to the engine upon establishment of a fuel cut condition including that a vehicle is in a coasting state where a throttle valve of the engine is fully closed, and an engine speed is equal to or higher than a predetermined value;
• executes a feedback control of an engagement torque of the lock-up clutch such that a slip amount of the lock-up clutch reaches a target slip amount upon establishment of a lock-up engagement condition including that the vehicle is in the coasting state;
• and
• executes a control of the automatic transmission for downshifting at a predetermined coast down vehicle speed so as to continue the fuel cut control in the coasting state;
• wherein
• the feedback control of the engagement torque of the lock-up clutch is temporarily stopped upon downshifting, and a performance ability of the feedback control of the slip amount is temporarily lowered upon resumption of the feedback control of the engagement torque of the lock-up clutch after the downshifting.

A vehicle drive control apparatus, comprising:

• an engine that generates power through combustion of fuel;
• an automatic transmission that transmits a reverse input from a driving wheel to the engine and automatically performs a gear shifting among a plurality of forward gear stages each having a different gear ratio;
• and
• a controller that:
• executes a fuel cut control for stopping supply of the fuel to the engine upon establishment of a fuel cut condition including that a vehicle is in a coasting state where a throttle valve of the engine is fully closed, and an engine speed is equal to or higher than a predetermined value;
• executes a control of the automatic transmission for downshifting at a predetermined coast down vehicle speed so as to continue the fuel cut control in the coasting state;
• and
• temporarily expands an air passage in an intake side of the engine while continuing execution of the fuel cut control during the downshifting.

A control method of a vehicle drive control apparatus including an engine that generates power through combustion of fuel, an automatic transmission that transmits a reverse input from a driving wheel to the engine and automatically performs a gear shifting among a plurality of forward gear stages each having a different gear ratio, and a fluid power transmission device having a lock-up clutch and interposed between the automatic transmission and the engine for transmitting power through fluid, the control method comprising:

• executing a fuel cut control for stopping supply of the fuel to the engine upon establishment of a fuel cut condition including that a vehicle is in a coasting state where a throttle valve of the engine is fully closed, and an engine speed is equal to or higher than a predetermined value;
• executing a control for engaging the lock-up clutch upon establishment of a lock-up clutch engagement condition including that the vehicle is in the coasting state;
• and
• executing a control of the automatic transmission for downshifting at a coast down vehicle speed that changes in accordance with a state of the lock-up clutch under the control for engaging the lock-up clutch.

A control method of a vehicle drive control apparatus including an engine that generates power through combustion of fuel, and an automatic transmission that transmits a reverse input from a driving wheel to the engine and automatically performs a gear shifting among a plurality of forward gear stages each having a different gear ratio, the control method comprising:

• executing a fuel cut control for stopping supply of the fuel to the engine upon establishment of a fuel cut condition including that a vehicle is in a coasting state where a throttle valve of the engine is fully closed, and an engine speed is equal to or higher than a predetermined value;
• executing a control of the automatic transmission for downshifting at a predetermined coast down vehicle speed so as to continue the fuel cut control in the coasting state;
• and
• executing a control of changing a downshifting speed such that the downshifting speed increases as an increase in a deceleration of the vehicle.

A control method of a vehicle drive control apparatus including an engine that generates power through combustion of fuel, an automatic transmission that transmits a reverse input from a driving wheel to the engine and automatically performs a gear shifting among a plurality of forward gear stages each having a different gear ratio, and a fluid power transmission device having a lock-up clutch and interposed between the automatic transmission and the engine for transmitting power through fluid, the control method comprising:

• executing a fuel cut control for stopping supply of the fuel to the engine upon establishment of a fuel cut condition including that a vehicle is in a coasting state where a throttle valve of the engine is fully closed, and an engine speed is equal to or higher than a predetermined value;
• executing a control for engaging the lock-up clutch upon establishment of a lock-up clutch engagement condition including that the vehicle is in the coasting state;
• executing a control of the automatic transmission for downshifting at a predetermined coast down vehicle speed so as to continue the fuel cut control in the coasting state;
• and
• executing a feedback control of an engagement torque of the lock-up clutch such that a slip amount of the. lock-up clutch reaches a target slip amount upon execution of the control of the automatic transmission for downshifting.

A control method of a vehicle drive control apparatus including an engine that generates power through combustion of fuel, an automatic transmission that transmits a reverse input from a driving wheel to the engine and automatically performs a gear shifting among a plurality of forward gear stages each having a different gear ratio, and a fluid power transmission device interposed between the automatic transmission and the engine for transmitting power through fluid, the fluid power transmission device having a lock-up clutch, the control method comprising:

• executing a fuel cut control for stopping supply of the fuel to the engine upon establishment of a fuel cut condition including that a vehicle is in a coasting state where a throttle valve of the engine is fully closed, and an engine speed is equal to or higher than a predetermined value;
• executing a feedback control of an engagement torque of the lock-up clutch such that a slip amount of the lock-up clutch reaches a target slip amount upon establishment of a lock-up engagement condition including that the vehicle is in the coasting state;
• and
• executing a control of the automatic transmission for downshifting at a predetermined coast down vehicle speed so as to continue the fuel cut control in the coasting state;
• wherein
• the feedback control of the engagement torque of the lock-up clutch is temporarily stopped upon downshifting, and a performance ability of the feedback control of the slip amount is temporarily lowered upon resumption of the feedback control of the engagement torque of the lock-up clutch after the downshifting.

A control method of a vehicle drive control apparatus including an engine that generates power through combustion of fuel, and an automatic transmission that transmits a reverse input from a driving wheel to the engine and automatically performs a gear shifting among a plurality of forward gear stages each having a different gear ratio, the control method comprising:

• executing a fuel cut control for stopping supply of the fuel to the engine upon establishment of a fuel cut condition including that a vehicle is in a coasting state where a throttle valve of the engine is fully closed, and an engine speed is equal to or higher than a predetermined value;
• executing a control of the automatic transmission for downshifting at a predetermined coast down vehicle speed so as to continue the fuel cut control in the coasting state;
• and
• temporarily expanding an air passage in an intake side of the engine while continuing execution of the fuel cut control during the downshifting.